Growth and characterization of PbSe and Pb1-xSnxSe on Si (100)

PbSe and Pb1-xSnxSe layers, with thicknesses ranging from 1 to 5 mu m, were grown by liquid phase epitaxy on Si (100) substrates using PbSe/BaF2/CaF2 buffer layers grown by molecular beam epitaxy. Optical Nomarski characteriz ation revealed excellent surface morphologies and good growth solution wipe offs. Although most PbSe layers were free of cracks over the entire 8 X8 mm (2) substrate area, ternary Pb1-xSnxSe layers exhibited varying crack densi ties ranging from zero in the center of samples to over 30 cracks/cm at the edges. High resolution x-ray diffraction (HRXRD) measurements of crack-fre e PbSe layers showed a residual in-plane tensile strain of 0.21% indicating that most of the 0.74% thermal expansion mismatch strain was absorbed by p lastic deformation. HRXRD full width half maxima values of less than 200 ar c sec showed that these layers also had high crystalline quality. Fourier t ransform infrared transmission measurements at room temperature and 110 K s howed absorption edges in the range of 270-80 meV, depending on temperature and tin content. This work shows that these materials should be suitable f or fabrication of mid-infrared devices covering the 4.6-16 mu m spectral ra nge. (C) 1999 American Institute of Physics. [S0021-8979(99)00510-1].